This invention relates to powertrains and, more particularly, to powertrains including electric power transfer units and mechanical gearing.
The advent of electric drive vehicles has given rise to a number of electromechanical power transmissions. More recently, it has been proposed to provide a fuel cell prime mover and an electro-mechanical transmission as the transmission within a vehicle powertrain.
The electromechanical transmission includes at least one electrical transfer machine, such as a motor/generator, and a source of electrical power. In many electromechanical transmissions, the source of power is an internal combustion engine, an electric power generator, again such as a motor/generator, and a battery assembly. The battery assembly, of course, adds and absorbs power during the operation of the transmission.
In a more recent proposal, the generator and internal combustion engine has been replaced with a fuel cell, such that the electro-mechanical transmission has a pure electric source of power for driving the transmission components. One such transmission can be found in U.S. Ser. No. 10/085,478 entitled xe2x80x9cVehicle Transmission with a Fuel Cell Power Source and a Multi-Range Transmissionxe2x80x9d and assigned to the assignee of the present invention.
It is an object of the present invention to provide an improved electromechanical powertrain having a fuel cell powered electro-mechanical transmission.
In one aspect of the present invention, the transmission employs two motor/generator units, which are supplied with electrical power from a fuel cell through an electronic control unit.
In another aspect of the present invention, a plurality of batteries is also supplied to provide power to the unit and absorb from the motor/generator units.
In yet another aspect of the present invention, a power takeoff drive mechanism is employed to operate accessories for the powertrain, such as cooling fans for the fuel cell and vehicle accessories.
In still another aspect of the present invention, one of the motor/generator units provides continuous driving power through a planetary gear arrangement to the power takeoff unit.
In yet still another aspect of the present invention, the other motor/generator unit supplies power to drive the vehicle through a separate planetary gearset.
In a further aspect of the present invention, the second power unit and planetary gearset have the output thereof controlled through a selectively engageable clutch assembly.
In a yet further aspect of the present invention, the first motor/generator unit is connectible with the transmission output shaft directly through a selectively engageable clutch mechanism.
In a still further aspect of the present invention, when the first motor/generator unit is connected to drive the output shaft directly, the second motor/generator unit and planetary gearset are shifted from a first range of operation to a second range of operation when the second motor/generator unit does not transmit power during this shift or ratio interchange.